The effect of an outbreak of the leaf miner Micrurapteryx salicifoliella on the performance of multiple Salix species in interior Alaska
2018
Wagner, Diane | Doak, Patricia
The genus Salix L. tends to be tolerant of herbivory, but severe outbreaks of herbivorous insects may compromise growth. First documented in Alaska in 1991, the willow leaf blotch miner, Micrurapteryx salicifoliella, is now responsible for frequent and widespread foliar damage to Salix in interior Alaska. We experimentally tested the effect of leaf mining on the performance of four susceptible Salix species across two years of outbreak, and placed the results in the context of a broader survey of leaf mining damage. Across the four species, reduction of leaf mining damage increased average stem elongation, numbers of leaves per shoot, and leaf area. Leaf mining damage was negatively related to leaf water content; a consequence of the leaf miner’s habit of breaching the cuticle on the underside of leaves. Growth deficits due to leaf mining are likely caused by both the loss of leaf tissue to leaf miner feeding and subsequent leaf desiccation. The results are notable in the context of a general decline in productivity in interior Alaska over the past few decades and because the leaf miner impacts Salix species also used by vertebrate browsers of cultural and economic importance, such as moose.
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